RAPID: A Community Test of Distributed Acoustic Sensing on the Ocean Observatories Initiative Regional Cabled Array

近年来，人们对太平洋西北部近海分布式声学传感(DAS)的潜力感兴趣，在这一地区进行测试将引起海洋界的广泛兴趣。在学术界，DAS是一种相对较新的观测技术，它用重复的激光脉冲询问光纤，并利用背向散射光的相位变化来测量光纤上的应变率。DAS可以工作在长达100公里的距离内，具有几米的空间分辨率和广泛的频率灵敏度。关于DAS信号如何对压力做出反应，仍有许多需要了解。在陆地上，DAS已被证明具有广泛的应用，包括地震监测和快速反应余震研究等。在海洋中的DAS实验更具挑战性。直到2019年，海底DAS在学术研究方面的潜力才得到展示。俄勒冈州边缘是世界上最具活力的海岸线之一，也是测试DAS能力的绝佳地点，因此，是研究风暴在海岸线附近产生地震噪声的作用并潜在地了解DAS是否以及如何可用于测量沉积物交换的理想地点。DAS还被确定为一项新技术，可能成为卡斯卡迪亚和其他地方未来海上地震和海啸预警系统的重要组成部分。计划中的关闭为在该地区测试DAS提供了一个很好的机会。加州理工学院的一名研究生将获得领导数据采集的经验，华盛顿大学的两名研究生将获得DAS/DTS数据采集方面的经验。PIS正在利用2021年11月初罕见的海洋天文台倡议(OOI)区域有线阵列(RCA)计划关闭的机会。随着RCA电缆与所有RCA岸边设备断开，分布式声学传感(DAS)和分布式温度传感(DTS)系统将连接到OOI光纤，并将接受测试，以确定海底DAS观测地震、海洋、声波和大地测量过程的潜力。DAS对于在卡斯卡迪亚开发近海地震和海啸预警系统的努力具有潜在的重要意义，该实验代表着在开发协议方面迈出的重要一步，该协议可以支持在满足国家安全要求的同时，在东北太平洋使用DAS进行科学和灾害缓解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In recent years, there has been interest in the potential of offshore distributed acoustic sensing (DAS) in the Pacific Northwest and a test in this region would be of widespread interest to the oceanographic community. DAS is a relatively new observational technique in academia that interrogates an optical fiber with repeated laser pulses and utilizes changes in the phase of backscattered light to measure the strain rate along the fiber. DAS can work to distances of up to ~100 km, has a spatial resolution of a few meters and a broad frequency sensitivity. There is still a lot to be learned about how the DAS signal responds to strain. On land, DAS has been demonstrated for a wide variety of applications including earthquake monitoring and rapid response aftershock studies etc. DAS experiments in the ocean are more challenging. It wasn’t until 2019 that the potential of seafloor DAS for academic research was demonstrated. The Oregon margin is one of the most energetic coastlines in the world and an excellent location to test the DAS capabilities and is thus, an ideal site to study the role of storms in generating seismic noise near coastlines and potentially understanding if and how DAS could be used for measuring sediment exchange. DAS has also been identified as a new technology that might form an important component of future offshore earthquake and tsunami early warning systems in Cascadia and elsewhere. The scheduled shutdown provides a great opportunity to test DAS in this region. A Caltech graduate student will get experience leading data acquisition and two UW graduate students will gain experience in DAS/DTS data acquisition. The PIs are taking advantage of a rare scheduled shutdown in early November 2021 of the Ocean Observatories Initiative (OOI) Regional Cabled Array (RCA). With the RCA cables disconnected from all RCA shoreside equipment, the distributed acoustic sensing (DAS) and distributed temperature sensing (DTS) systems will be connected to the OOI fibers and will undergo testing to determine the potential of submarine DAS to observe seismic, oceanographic, acoustic and geodetic processes. DAS is potentially of great importance for efforts to develop offshore earthquake and tsunami warning systems in Cascadia and this experiment represents an important step in developing protocols that can support the use of DAS for science and hazards mitigation in the Northeast Pacific while meeting national security requirements.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.